The Sankey diagram for the when an electric kettle is used to heat the water. 10 kJ raise the temperature of the kettle and 40 kJ escape to heat the surroundings is attached.
In this Sankey diagram, the arrows represent the flow of energy. The width of each arrow is proportional to the amount of energy flowing. The labels on the arrows indicate the amount of energy flowing in percent.
The Sankey diagram shows that 100 kJ of energy is initially input into the electric kettle. Of this energy, 40 kJ escapes to the surroundings as heat. The remaining 60 kJ of energy is used to heat the water in the kettle.